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Finding the Fourth Proportional to 499.95, 689.90 and 278.90

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Solution

The fourth proportional to 499.95, 689.90 and 278.90 is: 384.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    499.95 : 689.90 = 278.90 : x
  2. Step 2: Convert to fraction form
    499.95/689.90 = 278.90/x
  3. Step 3: Cross multiply
    499.95x = 689.90 × 278.90
  4. Step 4: Simplify right side
    499.95x = 192,410.48
  5. Step 5: Solve for x
    x = 192,410.48/499.95
  6. Step 6: Final answer
    x = 384.86

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.